Memory devices are typically provided as internal, semiconductor, integrated circuits in computers or other electronic systems. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and Flash memory.
Non-volatile memory is memory that can retain its stored data for some extended period without the application of power. Flash memory devices have developed into a popular source of non-volatile memory for a wide range of electronic applications. Flash memory devices are commonly used in electronic systems, such as personal computers, personal digital assistants (PDAs), digital cameras, digital media players, digital recorders, games, appliances, vehicles, wireless devices, cellular telephones, and removable memory modules, and the uses for Flash memory continue to expand.
Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Changes in threshold voltage of the cells, through programming of a charge storage structure, such as floating gates or trapping layers or other physical phenomena, determine the data state of each cell. Flash memory devices typically require relatively large voltages for programming and erasing operations. For example, a Flash memory device may have a supply voltage (e.g., Vcc) of 3V but require a voltage (e.g., Vpgm) of 15V or higher to be used during programming and/or erase operations on the array of memory cells. However, a sense (e.g., read) operation of Flash memory might only require voltages of Vcc or less, for example.
The demand for higher operating speeds and greater storage capacity in memory devices continues to increase. This demand is accompanied by a need for a reduction in the latency of signals propagating within memory devices in order to facilitate the desired increase in operating speed. However, along with a reduction in latency is the increased possibility of undesirable operating characteristics of a memory device if the various signals propagating in the memory device are not managed properly. For example, unintentionally generating program voltages during a read operation may cause undesirable results in the operation of the memory device.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for signal management circuits to facilitate the safe operation of non-volatile memories.